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    <script>
        //1.绝对值方法
        console.log(Math.abs(-1)); // 1
        console.log(Math.abs('-1')); // 1    隐式转换 会把字符串型 -1 转换为数字型
        //
        console.log(Math.abs(-Infinity)); // Infinity
        //
        console.log(Math.abs(NaN)); // NaN
        //
        console.log(Math.abs('pink')); // NaN
        //
        console.log(Math.abs(true)); // 1
        //2.三个取整方法
        //(1) Math.floor()  向下取整  往最小的整数取
        console.log(Math.floor(1.1)); // 1
        console.log(Math.floor(1.9)); // 1
        //(2) Math.ceil()  向上取整   往最大的整数取值
        console.log(Math.ceil(1.1)); // 2
        console.log(Math.ceil(1.9)); // 2
        //(3) Math.round() 四舍五入取  遇到 .5的话往正无穷位置取
        console.log(Math.round(4.5)); // 5
        console.log(Math.round(-1.5)); // -1
        console.log(Math.round(1.1)); // 1
        console.log(Math.round(1.9)); // 2
    </script>
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